New Technologies Bloom Together for Bettering Cancer Drug Conjugates

Abstract

Drug conjugates, including antibody-drug conjugates, are a step toward realizing Paul Ehr-lich’s idea from over 100 years ago of a “magic bullet” for cancer treatment. Through balancing selective targeting molecules with highly potent payloads, drug conjugates can target specific tumor microenviron-ments and kill tumor cells. A drug conjugate consists of three parts: a targeting agent, a linker, and a pay-load. In some conjugates, monoclonal antibodies act as the targeting agent, but new strategies for targeting include antibody derivatives, peptides, and even small molecules. Linkers are responsible for connecting the payload to the targeting agent. Payloads impact vital cellular processes to kill tumor cells. At present, there are 12 antibody-drug conjugates on the market for different types of cancers. Research on drug conjugates is increasing year by year to solve problems encoun-tered in conjugate design, such as tumor heterogene- ity, poor circulation, low drug loading, low tumor uptake, and heterogenous expression of target antigens. This review highlights some important preclinical research on drug conjugates in recent years. We focus on three significant areas: improvement of antibody-drug conjugates, identification of new conjugate targets, and development of new types of drug conjugates, including nanotechnology. We close by highlighting the critical barriers to clinical translation and the open questions going forward. Significance Statement——The development of anti-cancer drug conjugates is now focused in three broad areas: improvements to existing antibody drug conju-gates, identification of new targets, and development of new conjugate forms. This article focuses on the exciting preclinical studies in these three areas and advances in the technology that improves preclinical development.